Induction air distributors



March 27, 1962 A. JUDET DE LA CCMBE INDUCTION AIR DISTRIBUTORS FiledOct. 7, 1957 United States Patent 3,026,787 INDUCTION AIR DISTRIBUTORSAlbert Judet de la Combe, Lille, France, assignor to Societe Anonyme desEtablissements Neu, Lille, Nord, France, a corporation of France FiledOct. 7, 1957, Ser. No. 688,696 4 Claims. (Cl. 98-41) This inventionrelates to air distributors and has particular reference to improvedinduction air distributors. Induction air distributors characterized bythe use of nozzles through which a so-called primary air current isforced are already known, these nozzles being located in ducts ofadequate shape so that an external or secondary air stream is createdtherein.

The mixture of primary and secondary air is then distributed in thespace or room subsequent to a complementary treatment, such as heating,cooling, etc.

in all cases, a dilution of the primary air in the secondary air takesplace, which occasions a homogeneity, as the primary air may have a verylow or a very high temperature; the mixture of primary and secondary airwill have a temperature close to that of the air in the room.

However, in existing nozzle systems the efficiency of the operation isvery poor for it is well known that the efficiency of induction systemsof this character which utilize the kinetic energy of the primary air isquite moderate. Apparatus of this type actually require for theiroperation high running pressures of the order of 50 to 100 mm. of Hg.

Now such high pressures lead to serious inconveniences, notably that ofmaking the air-distributing apparatus rather noisy, unless it isprovided with a cumbersome sound-insulating device which is costly bothto manufac ture and in the energy required for overcoming its inherentlosses of pressure.

It is the essential object of this invention to provide an induction airdistributor consisting of a single spiralshaped passage in which the airis introduced tangentially so as to create a velocity field similar tothat of the socalled whirling type wherein the speed increases towardsthe centre at a rate inversely proportional to the radius.

This passage will preferably consist of a spiral volute with atangential inlet and an outlet port located on one side of the volute.If desired, this volute may comprise on the side opposite to the outletport a secondary air inlet.

According to another feature of this invention, the distributor isprovided at its periphery with a pipe or like member for discharging thedust particles centrifuged during the passage of the air stream throughthe apparatus.

Other features and advantages of the invention will appear as thefollowing descriptionproceeds with reference to the accompanying drawingforming part of this specification and illustrating diagrammatically byway of example a few forms of embodiment of the invention. In thedrawing:

FIGURE 1 is a diagrammatic elevational view showing a distributorconstructed in accordance with the teachings of this invention;

FIGURE 2 is a section taken upon the line A-A of FIG. 1;

FIGURE 3 is a section similar to FIG. 2 but showing a modifiedembodiment comprising a secondary air inlet, and

FIGURE 4 is a diagrammatical elevational view showing a distributorprovided with a pipe for discharging the centrifuged dust particles.

Referring to the drawing it is shown therein that the induction airdistributor according to the invention consists of a spiral-shapedvolute 1 having a tangential air inlet 3,026,787 Patented Mar. 27, 19622 and an air outlet port 3 on one of the lateral faces of the volute.

The air entering at 2 assumes a rotatory movement about the axis of thevolute and as it attains the edge of the outlet port 3 it has a hightangential velocity and is distributed in radial directions in the roomas in the case of radial diffusing air vents.

However, the field of speeds is such that in the vicinity of the voluteaxis the static pressure becomes strongly negative, thus creating astrong induction of air from the surrounding atmosphere, this airentering the distributor in large quantity. This air is carried along bythe rotatory movement in admixture with the primary air and is finallydischarged therewith as it attains the edge of the volute. Thisdischarge takes place, as already stated, in the fashion of a radialdiffusing air vent.

Thus, an induction air distributing apparatus is obtained which does notcomprise any duct or nozzle bound by walls between which the primary airflows at high speed and around which the secondary air is carried alongby friction at the outlet of this duct or nozzle.

On the contrary, in this improved device the primary air and thesecondary air are caused progressively to contact each other inside thenon-partitioned volume, over a large surface and according to a law ofthe vortex tube, this form of acceleration is characterized by a highefiiciency and has frequently been utilized in many industrialapplications.

With this system, an induction air distributorwhich may be termedinternal induction distributor-is obtained; it requires a moderateenergy and therefore its internal pressure loss is kept to a low levelso that a device constructed according to this invention operateswithout any sound insulating means with low-powered ventilatorsaffording a substantial saving in power; moreover, these ventilatorshave a moderate peripheral velocity and operate noiselessly, so that nocostly sound-insulating devices are required for overcoming theirinherent loss of pressure.

On account of the negative pressure existing in the central zone of thespiral-shaped distributor it is possible, according to another specificform of embodiment of the device of this invention which is shown inFIG. 3 of the drawing, to provide an orifice 4 of smaller diameter thanand opposite to the outlet port 3 for exhausting air from this oppositeside either directly or through a pipe or duct, the thus exhausted airbeing for example external air, i.e. exterior to the sheath 2, to thevolute 1 and/or the space communicating with the outlet 3.

In combination with this exhaust system it is possible to provide aregulating device consisting for example of a shutter 5 adapted to bedisplaced in the axial direction by means of a rod 9 solid therewith foradjusting the volume of air taken from the room in which the distributoris mounted.

By moving the shutter 5 from the orifice 4 to the port 3 in acontinuous, adjustable manner it is possible to vary at will the inputof air flowing through one or the other aperture, so that the inputsentering on both sides may be reduced or mixed in any suitableproportions. For the displacement of the shutter 5, the rod 9 carryingthe shutter is disposed to slide in a supporting spider 10 mounted inthe pipe 11 communicating with the opening 4. A control arm 12 isconnected to the rod 9 and laterally extends therefrom and is slidablydisposed in an axial slot 13 in the pipe 11.

To create a so-called whirl type field of velocities one may use notonly the device cited by way of example in the preceding example, whichcomprises a volute, but also any other system, for example a movable setof blades disposed annularly around the circular air outlet 3, this setof blades being mounted in an inlet case of adequate, non-directionalshape, or a rectilinear set of blades disposed at the inlet of the caseand adapted to deflect the air stream at the case inlet so as tosubsequently create the whirl tube.

The device according to this invention is also characterized by theessential advantage that a rotatory movement is imparted to the airtherein and that the velocity of the air flow in the vicinity of theoutlet port 3 is greater than that at the inlet '2; now, it is knownthat in a whirling'zone of speed the dust particles, droplets, etc.,and, as a rule, all foreign substances, are subjected to a field ofcentrifugal forces the action of which varies according to the specificweight, size and shape of the particles.

A known device called cyclone is based on this principle.

An internal-induction air distributor constitutes, due to its specificmode of operation, a cyclone in which the separation of certain dustparticles, droplets, soot particles, etc., is obtained, whereby thedistributor acts as a dust separator not only as regards the primary airinduced in the inlet 2 but also as regards the secondary air taken fromthe room and induced in the volute 1.

The dust particles, droplets and like foreign substances rotating in thewhirl tube are gradually forced outwards by the centrifugal force andcollected on the outer walls of the volute where they can be gathered ina slot or in any other suitable device, for example a port 6 as shown inFIG. 4. Then the dust-ladden air is expelled through a pipe 7 and eithervented or filtered prior to being recycled.

Although the attached drawings show only a few diagrammatic examples ofdevices constructed according to this invention, it will be readilyunderstood by anybody conversant with the art than many changes may bebrought to the shapes, relative proportions and materials utilized inthis construction without departing from the spirit and scope of theinvention as set forth in the appended claims.

I claim:

1. An internal-induction air distributor comprising a spiral shaped,internally unobstructed-to-spiral-movementof-air dilfusion body having aperipheral wall formed with a tangential air inlet adapted to be fed bya source of air under pressure and said body having opposing sides, oneof said sides being formed with a circular air outlet opening of asmaller diameter than the diameter of the body and the opposing sidebeing formed with a circular central air inlet disposed concentric withand of smaller diameter than the outlet and a shutter positioned in thebody tranverse to the axis of the central air inlet between the centralair inlet and the air outlet and movable between the central air inletand the air outlet relative to the air inlet for closing off said airinlet.

2. An internal-induction air distributor comprising a spiral shaped,internally unobstructed-to-spiral-movementof-air diffusion body having aperipheral wall formed with a tangential air inlet adapted to be fed bya source of air under pressure and said body having opposing sides, oneof said sides being formed with a circular air outlet opening of asmaller diameter than the diameter of the body and the opposing sidebeing formed with a circular central air inlet disposed concentric withand of smaller diameter than the outlet and a shutter positioned in thebody transverse to the axis of the central air inlet between the centralair inlet and the air outlet and said shutter being in the form of adisc of a diameter substantially equal to the diameter of the centralair inlet and being movablerelative to said air inlet to close off saidair inlet.

3. An internal-induction air distributor comprising a spiral shaped,internally unobstructed-to-spiral-movementof-air diffusion body having aperipheral wall formed with a tangential air inlet adapted to be fed bya source of air under pressure and said body having opposing sides, oneof said sides being formed with a circular air outlet opening of asmaller diameter than the diameter of the body and the opposing sidebeing formed with a circular central air inlet disposed concentric withand of smaller diameter than the outlet and a shutter positioned in thebody transverse to the axis of the central air inlet for movementbetween the central air inlet and the air outlet and said shutter beingin the form of a disc of a diameter substantially equal to the diameterof the central air inlet to close off said air inlet with said discbeing axially displaceable in the body.

4. An internal-induction air distributor comprising a spiral shapedinternally unobstructed-to-spiral-movementof-air diffusion body having aperipheral wall and opposing sides, one of said sides being formed withan air outlet of a smaller diameter than the diameter of the body andsaid peripheral wall of said body having a tangential air inlet adaptedto be fed by a source of air under pressure and being formed with atangential orifice for discharging the dust particles centrifugated inthe body and the opposing side having a circular air inlet disposedconcentric to the air outlet and being of less diameter than said airoutlet and a shutter positioned in the body transverse to the axis ofthe circular air inlet and disposed for axial movement in the bodyrelative to the air inlet and the air outlet in the sides.

References Cited in the file of this patent UNITED STATES PATENTS438,523 Bretney Oct. 14, 1890 578,192 Bates Mar. 2, 1897 1,643,966Swartwout Oct. 4, 1927 1,786,969 Van Der Heuel Dec. 20, 1930 2,296,314Slade Sept. 22, 1942 2,313,256 Morgan Mar. 9, 1943 2,373,741 CaldwellApr. 17, 1945 FOREIGN PATENTS 785,795 France May 27, 1935 658,471 GreatBritain Oct. 10, 1951 514,665 Italy Feb. 10, 1955 a All.

